This invention relates generally to apparatus for removing a tire from a wheel and is particularly directed to an arrangement for separating the bead of a tire from the wheel upon which it is mounted.
A tire bead is the inner portion of the tire in the shape of a projecting rim or band which is adapted to engage a peripheral portion of a wheel. The tire is provided with a pair of facing, spaced beads for secure mounting of the tire on the wheel in a sealed manner. Over long periods of use, a very strong seal may form between the tire bead and the wheel, particularly where rust has accumulated along the bead/wheel interface. While this increased seal strength is desirable from a safety standpoint, particularly in the case of tubeless tires, it presents a problem when it becomes necessary to remove the tire from the wheel for repair or replacement.
Early attempts to "break" the tire bead, as the separation of the tire bead from the wheel is termed in the art, involved striking the lateral walls of the tire in order to break the bead/wheel bond and loosen the tire. This frequently resulted in damage to the peripheral portion of the wheel, or its rim, particularly in the case of wheels comprised of a metal alloy such as chrome magnesium which is particularly brittle and subject to damage upon impact.
Later developments in this area made use of apparatus specifically designed for breaking the tire bead and removing the tire from its wheel. Such apparatus generally makes use of a cylinder operated by a hydraulic, pneumatic, or combination hydraulic and pneumatic control system and includes a bead engaging element disposed on the distal end of the cylinder's piston rod. The tire and wheel combination is typically oriented either vertically or horizontally during the tire removal procedure. Where the tire is oriented vertically, the tire generally must be raised onto the apparatus with great difficulty, particularly in the case of large truck tires, and must also be lifted with even greater difficulty for rotating the tire in order to separate the bead at various locations around the inner rim of the tire. In order to facilitate rotation of the tire and wheel combination, the apparatus is frequently provided with a bearing structure upon which the tire is positioned to facilitate its manual rotation. The bearings increase the cost and complexity of the apparatus which includes structure for supporting the vertically oriented tire and wheel combination which also substantially increases the size and weight of the apparatus.
Horizontal orientation of the tire requires considerable force to rotationally displace the tire to free its bead around the entire circumference thereof and to turn the tire over for releasing its other bead. In order to avoid dealing directly with the large weights and associated large handling forces required with the horizontally oriented tire, some approaches have made use of a portable tire bead separator which is mounted to the wheel and moved around its circumference to separate the entire tire bead. However, such portable units themselves generally weigh on the order of 50 pounds and require considerable strength to manipulate and operate.
The present invention is intended to overcome the aforementioned limitations of the prior art by means of a compact and portable apparatus wherein the tire is positioned in an orientation which facilitates its positioning upon and removal from the apparatus as well as its rotational displacement in an arrangement which also affords increased operator safety and more precise control of the tire bead breaking element to allow for its entirely remote control.